Climate negotiators were grappling for an agreement Saturday at the UN COP27 in Egypt after high-stakes talks went deep into the night with key sticking points over funding for countries wracked by climate disasters and ambition in tackling global warming.

The meeting at the Red Sea resort of Sharm el-Sheikh has been dominated by the controversial issue of climate "loss and damage" funds to help developing nations cope with the impacts of increasingly intense and costly floods, heatwaves, and droughts.

Wealthy nations, long reluctant to discuss the issue over fears of liability, have accepted that vulnerable nations are facing devastating impacts.

But there are disagreements over who pays and which countries are considered particularly affected.

With nations struggling to find common ground, Britain and several other countries circulated new suggestions trying to break the deadlock late Friday.

The issue was among a daunting list of outstanding areas of contention at the COP27 talks, where representatives from nearly 200 countries have gathered with the aim of driving forward action on climate change as the world faces a worsening onslaught of weather extremes.

Egyptian Foreign Minister Sameh Shoukry, who chairs the COP27 talks, told delegates on Friday — the day talks were officially due to end — that the negotiations would go into Saturday.

"I remain concerned at the number of outstanding issues," he said.

Delegates are looking to find agreement on emissions-cutting ambitions and reaffirm a goal to limit average warming to 1.5 degrees Celsius from pre-industrial levels, which scientists say is a safer guardrail to avoid the most dangerous impacts.

Pressure over $100-billion promise

Rich countries are also under pressure to finally fulfill promises to provide $100 billion a year to help developing countries green their economies and adapt to future impacts.

For many vulnerable countries, loss and damage is the defining issue of the conference, with some saying the success of the meeting hinges on the creation of a specific fund at the Egypt talks.

Richer nations, which have previously balked at the issue over fears of open-ended liability, have accepted that countries in the crosshairs of increasingly destructive climate-driven disasters need funding help, but have called for a broader set of donors — and prioritizing the most climate-vulnerable countries as recipients.

The G77 and China bloc of 134 developing countries launched an opening gambit on loss and damage this week, with a proposal to create a fund at COP27, with operational details to be agreed later.

A compromise response from the European Union, proposed late Thursday, suggested a fund specifically for the most vulnerable nations, saying the money should come from a "broad funder base" — code for countries including China and Saudi Arabia that have become wealthier since they were listed as developing nations in 1992.

Britain and several other countries have circulated a new draft proposal document, seen by AFP and confirmed by a source close to the negotiations, which suggested the fund could be part of a range of "funding arrangements".

The document, which has not been formally submitted to the UN process, suggested the new source of monies could be operationalized in two years.

But this would "only agree some ambiguous funding arrangements that kick the can down the road," said Mohamed Adow, of the think tank Power Shift Africa.